Vertical structure of turbulence on the southern flank of Georges Bank

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Microstructure and acoustic Doppler current profiler measurements were taken at two sites on Georges Bank: in a shallow (45 m) well‐mixed region on top of the bank and in a deeper (75 m) more stratified region on the southern flank. Each site was visited twice, April 25 to May 3, 1995, and June 6–16, 1995. At both sites the dominant variability in the turbulent kinetic energy dissipation rate ε was related to the semidiurnal M2 tide. In the well‐mixed lower portions of the water column a phase delay was observed between ε and the current speed. The delay increased with height above the bottom. There was also a depth‐dependent phase delay in the square of the vertical shear of horizontal velocity, S2, of the M2 component. This phase lag has a depth dependence similar to that found for ε, which suggests that the turbulent mixing is locally generated by the current shear, as opposed to having propagated from the boundary.